Cell lines and cell culture

The oral cancer cell lines, PE/CA-PJ15 [8] (source: ECACC) and Liv37K, a locally derived, low passage cell line, both showed detectable levels of iRhom2 expression and were selected to represent an established oral cancer cell model and a ‘close to the tumour’ oral cancer cell model, respectively. The normal oral keratinocyte cell line, NOK-hTERT [9] (Source: Prof Karl Münger, The Channing Laboratory, Brigham and Womens Hosptial, Boston, USA) was selected as a control. All cell lines were cultured at 37 °C in 5.0% carbon dioxide. Liv37K was used at or below passage 10 for all experiments reported here.

Cell monolayers were scraped into 10 ml PBS, followed by centrifugation to recover cell pellets which were stored at − 80 °C prior to protein extraction. The identity of the cell lines was confirmed by STR typing using GenePrint10® (Promega) and were mycoplasma negative by E-Myco PCR detection kit (CHEMBIO Ltd).